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Telescope Innovations Improve Speed, Accuracy of Eye Surgery

Sunday, 01 January 2012

NASA Technology

One of the main components of NASA’s vision
for the future of space exploration will actually
have a keen eye for the past. The James Webb
Space Telescope (JWST), scheduled to launch in 2018,
will have spectacular sight—after it reaches orbit, one of
its main goals is to observe the first galaxies that formed
in the early universe.

“JWST offers new capabilities in the infrared well
beyond what we can see from current telescopes, either
on the ground or in space. It will let us explore the early
universe, extrasolar planets, and really, all branches of
astrophysics,” says Lee Feinberg, optical telescope element
manager for the JWST at Goddard Space Flight Center.

Building such a keen space telescope is an astronomic
task. Because JWST will gaze over such incredible distances,
it requires very large mirrors. In fact, the primary
mirror will be more than two stories in diameter and
consists of 18 separate segments. Each segment must be
perfectly smooth, flat, and scratch-free in order to deliver
a view 13 billion light years away.

Construction of the 18 mirror segments involved
measuring, grinding, polishing, and testing—and more
measuring, grinding, polishing, and testing—and more
measuring, grinding, polishing, and testing (you get
the idea). One of the most time consuming steps of the
mirror development process—the grinding phase—can
take years.

Technology Transfer

To polish the JWST’s mirror segments, NASA’s
Goddard Space Flight Center contracted with Northrop
Grumman Aerospace Systems and Ball Aerospace, which
contracted with L3 Communications’ Tinsley Facility
in Richmond, California. A subcontractor to L3 at the
time, WaveFront Sciences of Albuquerque, New Mexico,
worked at the facility to assist with polishing by developing
a system for metrology (measurement) testing of the
large JWST mirrors after grinding. Called the infrared
Scanning Shack Hartmann System, the technology
enabled testing of the mirror’s surface immediately after
grinding and completely eliminated one of the polishing
steps in the process.

“It was a key advantage,” says Dan Neal, cofounder
of WaveFront Sciences. “They could take the mirror off
grinding and in one day, get a test back with a detailed
map on how to do the next step of the grinding.”

Neal explains how the new metrology testing stations
measured just a small part of the mirror to create an image
of the entire surface. “We didn’t have to build giant reference
mirrors. Traditionally, the reference mirror has to
be as big as the mirror you are going to test. It was very
innovative,” he says.

For NASA, the system reduced the time it took to construct
the high-quality primary mirror segments and also
reduced the cost. “By measuring earlier, in the grinding
phase, it allowed us to speed up the process and ensure
the performance was what we wanted when we got to the
final stages,” Feinberg says.

Now the innovation is enabling faster, more precise
measurements of complex surfaces for researchers and doctors
who measure a different kind of lens—the human eye.

“The testing systems developed for the JWST mirrors
have allowed improvements in the machines for testing
human eyes for Lasik surgery,” says Neal. “We were
trying to solve one problem for JWST, and the tool we
developed turned out to have many applications.”

Benefits

The work performed on the JWST spun off into one
of WaveFront Science’s products called the Complete
Ophthalmic Analysis System, or COAS. By incorporating
the algorithms developed for JWST, COAS performed 21
times faster.

Designed for diagnosing eye conditions and providing
a detailed map of the eye, COAS supports research
in cataracts, keratoconus (an eye condition that causes
reduced vision), and eye movement. “There are a number
of researchers around the United States and the world
using the product for vision research,” says Neal.

In 2007, Advanced Medical Optics acquired
WaveFront Sciences—and with it, the improved COAS
technology. Two years later, Advanced Medical Optics
was acquired by Abbott Laboratories and renamed
Abbott Medical Optics. Today, Abbott Medical Optics is
a leading company of vision correction technology based
in Santa Ana, California. The company recently released
a new product in Europe, based in part on COAS, called the iDesign Advanced WaveScan Studio. The technology is a main component of Abbott’s iLASIK laser vision
correction solution.

A doctor uses the iDesign Advanced WaveScan Studio
to measure a patient’s eye and then create a map of the
Lasik treatment that is needed for correction. The map
is transferred to a laser, which performs the custom treatment.
“It’s a stand-alone piece of equipment, but works
in conjunction with a laser. The software transfers directly
to the laser,” says Neal, who is now a research fellow at
Abbott Medical Optics.

According to the company, the technology is quick
and accurate. It works within 3 seconds to obtain four different
measurements, and provides accuracy in measuring
distorted surfaces—for conditions like nearsightedness,
farsightedness, astigmatism, and others. “The techniques
for JWST needed to be able to measure a wide variation
of shapes, and those are the same techniques we’ve used in
designing instruments to measure the eye,” says Neal.

JWST also prepared Abbott Medical Optics for
the large-format cameras that are now available in the
industry, says Neal. “We are using them in our new
products. When an eye doctor makes a measurement on
his machine, he doesn’t want to wait 2 minutes for it to
be complete. He wants to see it instantly. That’s taking
advantage of those faster and better algorithms,” he says.

“Often, the government has the ability to fund big
vision things and along the way, some of the technology
pieces turn out to be important across the board in many
different ways.”

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